Another A12P open baffle

Here's some photo's of my first open baffle project using A12P supported by 15" Fane Sovereign woofers. Alpairs currently being powered with a HLLY T90 soon to be replaced with a PA0901A from Twin Audio - which will be my first experience of tube sound. Woofers fed by a Crown XLS602, and MiniDSP taking care of the crossover and equalisation. Drivers only have about 50hrs breaking-in so far, but first impressions when I started listening to the finished speakers this weekend were very promising. :)

Matt
 

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Hello Matt,
Great work, very stylish! Always good to projects like this as they give high-street offerings a run for their expensive money.

You'll need another 150+ hours on the Alp12P's at low vols to get them better run-in. Tony's PA0901A should work well. Its a copy of Derek Shek's excellent Miniwatt. Not sure what Tony's got in amp stock at the moment but I'd be tempted to ask him if there's any nice small vintage tubie amps he could dust off and sell you.

Cheers
Mark.
 
Mark, maybe you can say couple of words here, what will be a difference between 12P and 10 for this application? Thanks.

Sure,
From the function perspective:

The 12P has the single mechanical (semi free to air) suspension system which has more progressive load resistance. Its spider does all the mechanical operation of the power-train, the front suspension acting primarily as an air seal and partial damper. This driver's design is well suited to the type(s) of open project application like/similar to Matt's.

The Alp10 Gen. 2 has a long throw linear suspension design better suited to ported/vented and sealed systems. The 10 can be used on open applications but more care is needed to limit/control its LF output.

Should I have time to make an open baffle project, I'd personally use the 12P as my first choice. Re woofers, my choice(s) would be influenced by the design of their power-trains, paying particular attention to the cone's total depth, the number of radii deployed across its surface substrate and its moving mass, see post 120 on this thread:

http://www.diyaudio.com/forums/markaudio/224477-future-woofer-production-12.html

Thanks
Mark.
 
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I'm not Mark, but I have experimented with both 'open' A10 and A12, but not at the same time like A vs B on same baffle.

In OB you might get 50Hz lower extension from A12 against A10. I think due to the extra Sd of A12. Other than this, the different sonic flavour of either driver will apply.
Either could work, also the A7. I'm not sure you can say one is categorically 'best'. Either driver will have it's strengths &/or trade off against another. My really general advice would be 'the bigger the room, chose the bigger Sd driver'. In a smaller room, more near field the A10 or A7 might work very well also.
 
do you really need that extra 50Hz extension and problem with LF output?
Technically no, it's only 50Hz. But an A12 pencil will sound a bit different to an A10 pencil. It's the sound of a bigger, paper membrane vs the sound of a smaller, lighter, metal membrane. Having experimented with them both I'd lean towards the A12 in a larger room. Smaller room I'd try the A10 or A7, but all could work.
 
Technically no, it's only 50Hz. But an A12 pencil will sound a bit different to an A10 pencil. It's the sound of a bigger, paper membrane vs the sound of a smaller, lighter, metal membrane. Having experimented with them both I'd lean towards the A12 in a larger room. Smaller room I'd try the A10 or A7, but all could work.

Tims's made good practical points.

I'd add by saying the driver's power-train function is important for OB applications as the "free air" environment offers no damping. The 12P would be the more observant choice. I'd still be tempted to use the 12P on smaller(ish) OB projects/rooms as its dispersion pattern and central stereo image are wider than the 10 Gen.2 (cone acreage counts) likely benefitting OB set-ups. Common sense should be applied if your room is "small", down-size the drivers/OB project design.

Thx
Mark
 
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